17,790 research outputs found

    Investigation of Anaplasma marginale Seroprevalence in a Traditionally Managed Large California Beef Herd.

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    Recent observations by stakeholders suggested that ecosystem changes may be driving an increased incidence of bovine erythrocytic anaplasmosis, resulting in a reemerging cattle disease in California. The objective of this prospective cohort study was to estimate the incidence of Anaplasma marginale infection using seroconversion in a northern California beef cattle herd. A total of 143 Black Angus cattle (106 prebreeding heifers and 37 cows) were enrolled in the study. Serum samples were collected to determine Anaplasma marginale seroprevalence using a commercially available competitive enzyme-linked immunosorbent assay test kit. Repeat sampling was performed in seronegative animals to determine the incidence density rate from March through September (2013). Seroprevalence of heifers was significantly lower than that of cows at the beginning of the study (P < 0.001) but not at study completion (P = 0.075). Incidence density rate of Anaplasma marginale infection was 8.17 (95% confidence interval: 6.04, 10.81) cases per 1000 cow-days during the study period. Study cattle became Anaplasma marginale seropositive and likely carriers protected from severe clinical disease that might have occurred had they been first infected as mature adults. No evidence was found within this herd to suggest increased risk for clinical bovine erythrocytic anaplasmosis

    Discovery and Cosmological Implications of SPT-CL J2106-5844, the Most Massive Known Cluster at z>1

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    Using the South Pole Telescope (SPT), we have discovered the most massive known galaxy cluster at z>1, SPT-CL J2106-5844. In addition to producing a strong Sunyaev-Zel'dovich (SZ) effect signal, this system is a luminous X-ray source and its numerous constituent galaxies display spatial and color clustering, all indicating the presence of a massive galaxy cluster. Very Large Telescope and Magellan spectroscopy of 18 member galaxies shows that the cluster is at z = 1.132^(+0.002)_(–0.003). Chandra observations obtained through a combined HRC-ACIS GTO program reveal an X-ray spectrum with an Fe K line redshifted by z = 1.18 ± 0.03. These redshifts are consistent with the galaxy colors found in optical, near-infrared, and mid-infrared imaging. SPT-CL J2106-5844 displays extreme X-ray properties for a cluster having a core-excluded temperature of T_X = 11.0^(+2.6)_(–1.9) keV and a luminosity (within r _(500)) of LX (0.5-2.0 keV) = (13.9 ± 1.0) × 10_(44) erg s^(–1). The combined mass estimate from measurements of the SZ effect and X-ray data is M_(200) = (1.27 ± 0.21) × 10^(15) h ^(–1) _(70) M_⊙. The discovery of such a massive gravitationally collapsed system at high redshift provides an interesting laboratory for galaxy formation and evolution, and is a probe of extreme perturbations of the primordial matter density field. We discuss the latter, determining that, under the assumption of ΛCDM cosmology with only Gaussian perturbations, there is only a 7% chance of finding a galaxy cluster similar to SPT-CL J2106-5844 in the 2500 deg^2 SPT survey region and that only one such galaxy cluster is expected in the entire sky

    Estimating Linkages between Redfish and Cold Water Coral on the Norwegian Coast

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    The importance of essential fish habitat in supporting commercial fisheries has received increasing attention in recent years. Bottom trawling is known to cause particularly destructive damage to habitat that is effectively non-renewable, such as cold water corals. This paper applies the production function approach to estimate the link between cold water corals and redfish in Norway. Both the carrying capacity and growth rate of redfish are found to be functions of cold water coral habitat and thus cold water corals can be considered an essential fish habitat. The paper also estimates a facultative relationship between cold water coral and redfish stocks. The essential habitat model shows the best fit to the data. Comparative statics of an essential habitat indicate an approximate annual loss in harvest of between 11 and 29% within the bounds of coral decline estimated by scientists. In terms of policy, our results indicate that essential fish habitat protection should be considered when managing commercially important species.Cold water coral, redfish, production function, habitat-fishery linkages, essential fish habitat, International Development, Research Methods/ Statistical Methods, Q22,

    The birth memories and recall questionnaire (BirthMARQ): development and evaluation

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    Background: Childbirth is a challenging and emotive experience that is accompanied by strong positive and/or negative emotions. Memories of birth may be associated with how women cognitively process birth events postpartum and potentially their adaptation to parenthood. Characteristics of memories for birth may also be associated with postnatal psychological wellbeing. This paper reports the development and evaluation of a questionnaire to measure characteristics of memories of childbirth and to examine the relationship between memories for birth and mental health. Methods: The Birth Memories and Recall Questionnaire (BirthMARQ) was developed by generating items from literature reviews and general measures of memory characteristics to cover dimensions relevant to childbirth. Fifty nine items were administered to 523 women in the first year after childbirth (M = 23.7 weeks) as part of an online study of childbirth. Validity of the final scale was checked by examining differences between women with and without probable depression and PTSD. Results: Principal components analysis identified 23 items representing six aspects of memory accounting for 64% of the variance. These were: Emotional memory, Centrality of memory to identity, Coherence, Reliving, Involuntary recall, and Sensory memory. Reliability was good (M alpha = .80). Women with probable depression or PTSD reported more emotional memory, centrality of memories and involuntary recall. Women with probable depression also reported more reliving, and those with probable PTSD reported less coherence and sensory memory. Conclusion: The results suggest the BirthMARQ is a coherent and valid measure of the characteristics of memory for childbirth which may be important in postnatal mood and psychopathology. While further testing of its reliability and validity is needed, it is a measure capable of becoming a valuable tool for examining memory characteristics in the important context of childbirth

    Network Models

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    Networks can be combined in various ways, such as overlaying one on top of another or setting two side by side. We introduce "network models" to encode these ways of combining networks. Different network models describe different kinds of networks. We show that each network model gives rise to an operad, whose operations are ways of assembling a network of the given kind from smaller parts. Such operads, and their algebras, can serve as tools for designing networks. Technically, a network model is a lax symmetric monoidal functor from the free symmetric monoidal category on some set to Cat\mathbf{Cat}, and the construction of the corresponding operad proceeds via a symmetric monoidal version of the Grothendieck construction.Comment: 46 page
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